1. Field of the Invention
The present invention relates to a configuration of an end of linear fastener elements in a space portion of a fastener chain in which coil type or zigzag type linear fastener elements molded of thermoplastic resin monofilament are attached to a fastener tape. It also relates to a method and an apparatus for forming such an end of the linear fastener elements.
2. Description of the Related Art
Conventionally, when a single unit of slide fastener is produced by cutting a continuous slide fastener chain, in which coil-shaped fastener elements made of thermoplastic resin are attached to a fastener tape, at each space portion which is provided at a predetermined interval on the fastener chain, an upper stopper device or a lower stopper device is attached to the coil-shaped fastener elements in a state that an end of the coil-shaped fastener elements is cut to be a cut end portion 7xe2x80x2 as shown in FIG. 33.
When the slide fastener in this form is employed on clothes or the like, it may injury the skin of a wearer or catch on his underwear so that an unexpected accident may occur. This point has been improved in a slide fastener as shown in FIG. 34 and disclosed in Japanese Utility Model Publication No. 46-16573. In this slide fastener, linear fastener elements 1xe2x80x3 made of thermoplastic resin are sewed onto a side edge portion of a fastener tape 2xe2x80x3 with sewing yarns 15xe2x80x3, and an upper stopper device 10xe2x80x3 is attached to an end of the linear fastener elements 1xe2x80x3 such that it is attached over the linear fastener elements 1xe2x80x3. Further, the end of the linear fastener elements 1xe2x80x3 existing outside the upper stopper device 10xe2x80x3 are melted by heating in that state and fused with the fastener tape 22 so as to form a fused portion 8xe2x80x3.
In the slide fastener as described above and shown in FIG. 34, the upper stopper device 10xe2x80x3 is attached to the linear fastener elements 1xe2x80x3 made of thermoplastic resin and then, the linear fastener element 1xe2x80x3 existing at a upper end side of the upper stopper device 10xe2x80x3 is melted by a heating means and fused to the fastener tape 2xe2x80x3 so as to form the fused portion 8xe2x80x3. Thus, the fused portion 8xe2x80x3 is solidified on the fastener tape 2xe2x80x3 such that it protrudes from an edge portion of the fastener tape 2xe2x80x3. Therefore, there is a problem that because the fused portion 8xe2x80x3 is hard, the wearer may feel a physical discomfort and uncomfortable when it touches his skin.
Accordingly, the present invention has been achieved in views of the above described problems. A main object of the present invention is to provide a slide fastener chain in which a cut end potion of linear fastener elements in the fastener chain is formed in a safety form not having a danger of injuring the skin of a wearer or catching on his underwear, and in which the end of the linear fastener elements is fixed onto a fastener tape of the slide fastener chain in a stabilized state. Therefore, it is possible to finish the slide fastener chain with an upper stopper device or a lower stopper device, or a box pin and a separable pin of a separable stopper device attached in a safety state, so that the slide fastener chain can be used comfortably for a long time while not providing a feeling of a physical discomfort to the wearer.
Another object of the present invention is to provide a slide fastener chain which can be used with safety in a stabilized state when the slide fastener is operated, by specifying the cut end potion position of the linear fastener elements in the fastener chain and a fused form of the linear fastener elements at the cut end potion thereof to be fused to the fastener tape.
Still another object of the present invention is to provide a slide fastener chain in which a space portion can be produced in the fastener chain simply without considering a coiling direction of the coil-shaped fastener elements in the fastener chain or a disposition of an inverted portion of zigzag shaped fastener elements.
Still another object of the present invention is to provide a slide fastener chain allowing the end of the linear fastener elements in the fastener chain to be processed accurately so as to produce a safety form of the fastener chain.
Still another object of the present invention is to provide a slide fastener chain in which the end of the linear fastener elements in the fastener chain is processed in a stabilized state, and then an upper stopper device, a lower stopper device or a box pin and separable pin of a separable stopper device is attached, so that a comfortable use of the slide fastener can be achieved for a long time.
Still another object of the present invention is to provide a method for forming a cut end potion of thermoplastic-resin-made coil type or zigzag type linear fastener elements of a slide fastener chain in a stabilized configuration, which can be attached to the fastener tape securely.
Still another object of the present invention is to provide a method for forming a cut end potion of thermoplastic-resin-made coil type or zigzag type linear fastener elements of a continuous slide fastener chain with ease in a stabilized configuration.
To achieve the above object, according to a first aspect of the present invention, there is provided a slide fastener chain including coil type or zigzag type linear fastener elements of thermoplastic resin attached to a side edge portion of a fastener tape, wherein an end of the linear fastener elements has a fused portion formed by fusing the fastener element at said end to the fastener tape by heating in such a manner that a cut end potion of the end of the linear fastener elements is located inward of the side edge portion, and the cut end potion of the end of the linear fastener elements is located so as not to project from the side edge portion of the fastener tape.
Preferably, according to the first aspect of the present invention, the end of the coil type or zigzag type linear fastener elements has the fused portion formed by fusing the fastener element at said end to the fastener tape by heating in such a manner that the cut end potion of the end of the linear fastener elements is pushed inward of the side edge portion of the fastener tape.
Further, it is preferable that cut end potion of the end of the coil type or zigzag type linear fastener elements is provided by cutting a leg portion of the fastener element at said end which faces and is in contact with the fastener tape, and the fused portion is formed by fusing an inverted portion of the linear fastener element at said end to the fastener tape by heating.
Alternatively, the cut end potion of the end of the coil type or zigzag type linear fastener elements may be provided by cutting a leg portion of the linear fastener element at the end which faces and is in contact with the fastener tape, and the fused portion is formed by fusing the cut leg portion to the fastener tape by heating.
Further alternatively, the cut end potion of the end of the coil type or zigzag type linear fastener elements may be provided by cutting a leg portion of the linear fastener element at the end which faces and is in contact with the fastener tape, and the fused portion is formed by fusing the cut leg portion and an inverted portion to the fastener tape by heating.
Further, it is preferable that the cut end potion of the end of the coil type or zigzag type linear fastener elements is provided by cutting an upper leg portion at the end which is disposed apart from a surface of the fastener tape, and the fused portion is formed by fusing the cut upper leg portion and an inverted portion to the fastener tape by heating.
Furthermore, it is preferable that the cut end potion of the end of the coil type or zigzag type linear fastener elements is located below a core thread or a blade attached at the linear fastener elements and is fused to the fastener tape in a state that the cut end potion is nipped between the core thread or blade and the fastener tape.
Alternatively, it is preferable that the cut end potion of the end of the coil type or zigzag type linear fastener elements is located below a fixing yarn such as a sewing yarn, warp yarn or warp knitting yarn, for fixing the linear fastener elements onto the fastener tape, and the cut end potion is fused to the fastener tape in a state that the cut end potion is nipped between the fixing yarn and the fastener tape.
Further, it is preferable that an upper stopper device or a lower stopper device is attached to the coil-type or zigzag type linear fastener elements at a position adjacent to the fused portion formed on the linear fastener elements.
Alternatively, it is preferable that an upper stopper device, a lower stopper device, or a set of box pin and separable pin of a separable stopper device is attached so as to cover the fused portion formed on the coil type or zigzag type linear fastener elements.
According to a second aspect of the present invention, there is provided a method for forming an end of a slide fastener chain in which coil type or zigzag type linear fastener elements made of thermoplastic resin are attached to a side edge portion of a fastener tape, comprising steps of cutting a leg portion at said end of the linear fastener elements to form a cut end potion; pushing the cut end potion of the linear fastener elements inward of the side edge portion of the fastener tape; and with maintaining that pushed state, fusing the end of the linear fastener elements to the fastener tape by heating.
Further preferably, in forming the end of the slide fastener chain at each space portion of the slide fastener chain where coil type or zigzag type linear fastener elements are attached, the method comprises steps of: forwarding a pair of pushing members into the space portion of the fastener chain; hauling the fastener chain at the space portion so as to locate front and back cut end portions of the space portion at the pushing members and at the same time, pressing the linear fastener elements to be separated in lateral directions thereof while contacting the cut end potions of the linear fastener elements with the pushing members; and pushing each of the cut end potions inward of the side edge portion of the fastener tape.
Furthermore, it is preferable that the method for forming the end of the slide fastener chain comprises a step of, with the cut end potion of said end of the coil type or zigzag type linear fastener elements being pushed inward of the side edge portion of the fastener tape, fusing an inverted portion of the fastener element at said end to the fastener tape by heating.
Still further, it is preferable the method for forming the end of the slide fastener chain comprises steps of: pressing the side edge portions of a pair of left and right fastener tapes in lateral directions thereof by each of the pushing member when the pushing members ascend to contact with the side edge portions; and bending the side edge portions of the fastener tapes in a predetermined direction, for example, downward to enlarge a gap between the pair of left and right fastener tapes and at the same time, pushing forcibly the cut end potions of the coil type or zigzag type linear fastener elements inward of the side edge portions of the fastener tapes.
Alternatively, it is preferable that the method for forming the end of the slide fastener chain comprises steps of: pressing the cut end potions formed at the ends of the coil type or zigzag type linear fastener elements attached to the side edge portions of a pair of fastener tapes in lateral directions thereof by each of the pushing members when the pushing members descend to contact with the cut end potions, to separate only the cut end potions of the linear fastener elements in lateral directions thereof and forcibly pushing them inward of the side edge portions of the fastener tapes.
According to a third aspect of the present invention, there is provided an apparatus for forming an end of a slide fastener chain, comprising: a transfer path formed on a top face of a die for transferring a continuous slide fastener chain having space portions to an end-forming mechanism and discharging the slide fastener chain after the ends are formed, a gap portion provided in a middle portion of the end-forming mechanism at the transfer path, an arm movable in and out of the gap portion for pushing down the continuous slide fastener chain being transferred above the gap portion, a pair of pushing members disposed in front and back of the gap portion and projectable toward the transfer path for pushing cut end potions of linear fastener elements projecting from side edge portion of a pair of fastener tapes inwardly, a ultrasonic horn disposed so as to face parts of the die corresponding to the pushing members and movable toward and away from the die, so that the cut end potions of the linear fastener elements at the space portion at the end of the continuous slide fastener chain are fused to and formed on the fastener tapes in such a manner that the cut end potions of the ends of the linear fastener elements does not project from the side edge portions of the fastener tapes.
Further, it is preferable that the pushing member disposed in each of front and back of the gap portion has a taper surface at an end surface thereof to contact with linear fastener elements so that the cut end portions of the linear fastener elements are smoothly pushed inward of the side edge portions of the fastener tapes.
Furthermore, it is preferable that the die is provided with a guide groove through which the pushing member is slidably movable up and down in such a manner that the pushing member can come in and out of an upper surface of the guide groove.
Still further, it is preferable that the ultrasonic horn disposed above the die is provided with an insertion groove in which the pushing member can be inserted.
Still further, it is preferable that the die is provided with a recessed portion on each of opposite sides of an end portion of the guide groove so that the side edge portion of the fastener tape can be bent and accommodated in the recessed portion.
Still further, it is preferable that the ultrasonic horn is provided with a cut-out portion on each of opposite sides of an end portion of the insertion groove so that a core thread, fixing yarn or blade can be accommodated and pressed in the cut-out portion.
It is also preferable that the ultrasonic horn disposed above the die is provided with a guide groove through which the pushing member is slidably movable up and down so as to come in and out of a lower surface of the guide groove.